import { test } from 'node:test';
import assert from 'node:assert/strict';
import { mkdtempSync, writeFileSync, rmSync, readFileSync } from 'node:fs';
import { tmpdir } from 'node:os';
import { join } from 'node:path';
import { execFileSync } from 'node:child_process';
import { Git } from './git.js';

function g(cwd, args) {
  return execFileSync('git', args, { cwd, encoding: 'utf8' });
}

/** 建立 bare remote + working clone，於 target/source 製造會衝突的變更。 */
function setupRepo() {
  const root = mkdtempSync(join(tmpdir(), 'git-test-'));
  const bare = join(root, 'remote.git');
  const work = join(root, 'work');
  execFileSync('git', ['init', '-q', '--bare', bare]);
  execFileSync('git', ['clone', '-q', bare, work]);
  g(work, ['config', 'user.email', 'test@example.com']);
  g(work, ['config', 'user.name', 'tester']);
  g(work, ['config', 'commit.gpgsign', 'false']);

  writeFileSync(join(work, 'file.txt'), 'base\n');
  g(work, ['add', '-A']);
  g(work, ['commit', '-q', '-m', 'base']);
  const def = g(work, ['rev-parse', '--abbrev-ref', 'HEAD']).trim();

  g(work, ['checkout', '-q', '-b', 'target']);
  writeFileSync(join(work, 'file.txt'), 'target change\n');
  g(work, ['commit', '-qam', 'target change']);

  g(work, ['checkout', '-q', def]);
  g(work, ['checkout', '-q', '-b', 'source']);
  writeFileSync(join(work, 'file.txt'), 'source change\n');
  g(work, ['commit', '-qam', 'source change']);

  g(work, ['push', '-q', 'origin', 'target', 'source', def]);
  return { root, bare, work };
}

test('detectConflict: 偵測到衝突並回傳衝突檔，事後還原暫存分支', () => {
  const { root, bare, work } = setupRepo();
  try {
    const git = new Git({ cwd: work, remoteUrl: bare, token: 'x' });
    git.configure();
    git.fetchBranches(['target', 'source']);

    assert.ok(git.countAheadCommits('target', 'source') >= 1);

    const det = git.detectConflict('target', 'source');
    assert.equal(det.hasConflict, true);
    assert.ok(det.files.includes('file.txt'));

    // 暫存分支應已清除
    assert.ok(!g(work, ['branch']).includes('__conflict_check'));
  } finally {
    rmSync(root, { recursive: true, force: true });
  }
});

test('createResolveBranch: 推送含衝突標記的解衝突分支到 remote', () => {
  const { root, bare, work } = setupRepo();
  try {
    const git = new Git({ cwd: work, remoteUrl: bare, token: 'x' });
    git.configure();
    git.fetchBranches(['target', 'source']);

    const res = git.createResolveBranch({ target: 'target', source: 'source', resolveBranch: 'resolve-x' });
    assert.ok(res.files.includes('file.txt'));

    // remote 應有 resolve-x 分支
    assert.ok(execFileSync('git', ['--git-dir', bare, 'branch'], { encoding: 'utf8' }).includes('resolve-x'));
    // 已 commit 的檔案應保留衝突標記
    assert.ok(readFileSync(join(work, 'file.txt'), 'utf8').includes('<<<<<<<'));
  } finally {
    rmSync(root, { recursive: true, force: true });
  }
});

test('detectConflict: 可順利合併時回報無衝突', () => {
  const root = mkdtempSync(join(tmpdir(), 'git-test-'));
  try {
    const bare = join(root, 'remote.git');
    const work = join(root, 'work');
    execFileSync('git', ['init', '-q', '--bare', bare]);
    execFileSync('git', ['clone', '-q', bare, work]);
    g(work, ['config', 'user.email', 'test@example.com']);
    g(work, ['config', 'user.name', 'tester']);
    g(work, ['config', 'commit.gpgsign', 'false']);

    writeFileSync(join(work, 'a.txt'), 'base\n');
    g(work, ['add', '-A']);
    g(work, ['commit', '-qm', 'base']);
    const def = g(work, ['rev-parse', '--abbrev-ref', 'HEAD']).trim();

    g(work, ['checkout', '-q', '-b', 'target']); // target 不動
    g(work, ['checkout', '-q', def]);
    g(work, ['checkout', '-q', '-b', 'source']);
    writeFileSync(join(work, 'b.txt'), 'new file\n'); // 改不同檔，無衝突
    g(work, ['add', '-A']);
    g(work, ['commit', '-qm', 'add b']);
    g(work, ['push', '-q', 'origin', 'target', 'source', def]);

    const git = new Git({ cwd: work, remoteUrl: bare, token: 'x' });
    git.configure();
    git.fetchBranches(['target', 'source']);
    const det = git.detectConflict('target', 'source');
    assert.equal(det.hasConflict, false);
    assert.deepEqual(det.files, []);
  } finally {
    rmSync(root, { recursive: true, force: true });
  }
});